A recent study from investigators at Massachusetts General Hospital and Harvard Medical School is underlining the importance of receiving booster doses of COVID-19 vaccines among solid organ transplant recipients.
Results of the study, which included more than 30 lung or heart transplant recipients, suggest patients began to develop diminished and delayed antibody responses with the first two COVID-19 mRNA vaccine doses, but experienced significantly greater responses following their third dose.1
“Our findings highlight that effective protection of most transplant recipients is achievable but requires the recommended additional doses of vaccine. However, for most individuals, cross-protection of their responses to currently circulating immune-evasive SARS-CoV-2 variants is attenuated. The multiple subsequent vaccine doses recommended for transplant recipients are likely critical for maintaining immunity,” said co-senior investigator Marcia B. Goldberg, MD, director of the Office of Research Careersin the Division of Infectious Diseases at Massachusetts General Hospital and a professor in the Departments of Medicine and Microbiology at Harvard Medical School.2
During the peak of the COVID-19 pandemic, a large public health effort was implemented to alert the general public those with preexisting conditions were at-risk of increased disease severity, including organ transplant recipients. After the introduction of COVID-19 vaccines, both the American Heart Association and American Lung Association released documents in 2021 endorsing the use of booster doses among heart and lung transplant recipients, respectively.3,4
In the current study, Goldberg and a team of investigators sought to provide the community with further insight into the kinetics and variant cross-protection of vaccine-induced antibodies among heart and lung transplant recipients receiving SARS-CoV-2 mRNA 3-dose vaccination series. With this in mind, investigators designed their study as a prospective longitudinal analysis of data obtained from patients receiving care at Massachusetts General Hospital.1
In total, investigators identified 18 lung and 17 heart transplant recipients, as well as 7 nontransplanted patients with cystic fibrosis, for inclusion. Investigators also identified 12 nonimmunosuppresed healthy volunteers matched with study participants based on age and residence. Of note, all patients were at least 18 years of age or older and lived in eastern Massachusetts.1
For the purpose of analysis, investigators measured longitudinal serum antibody and neutralization responses against the ancestral and major variants of SARS-COV-2 before, during, and after the mRNA. Investigators pointed out serial blood samples were collected from all participants immediately prior and 1 week after each vaccine dose as well as 2, 3, and 6 months after dose 2 and 1 and 3 months after dose 3.1
Upon analysis, investigators observed strong anti-spike responses immediately following vaccination and cross-neutralization against all variants among the healthy controls included in the study. However, increases in antibody concentrations occurred gradually following the first 2 doses among transplant recipients and cross-neutralization was completely absent against the Omicron B.1.1.529 variant.1
Further analysis suggests 73% of transplant recipients experienced a significant response to the third vaccine dose, with these patients achieving levels comparable to those of the healthy controls. Investigators highlighted these patients also experienced attenuated neutralization of immune evasive variants, particularly Beta, Gamma, and Omicron. Additional analyses revealed the non-transplanted patients with cystic fibrosis had responses to vaccine doses similar to those of the healthy controls.1
“Next steps are to analyze the cellular immune responses of solid organ transplant recipients over the same longitudinal time frame,” Goldberg added.2
Liew MY, Mathews JI, Li A, et al. Delayed and Attenuated Antibody Responses to Coronavirus Disease 2019 Vaccination With Poor Cross-Variant Neutralization in Solid-Organ Transplant Recipients-A Prospective Longitudinal Study. Open Forum Infect Dis. 2023;10(8):ofad369. Published 2023 Aug 10. doi:10.1093/ofid/ofad369
Transplant Recipients Experience Limited protection with primary COVID-19 vaccination series, but third dose boosts response. Massachusetts General Hospital. August 10, 2023. Accessed August 16, 2023. https://www.massgeneral.org/news/press-release/transplant-recipients-covid-vaccination.
3rd covid-19 vaccine dose recommended for heart transplant patients and others with weakened immune systems. American Heart Association. August 17, 2021. Accessed August 16, 2023. https://newsroom.heart.org/news/3rd-covid-19-vaccine-dose-recommended-for-heart-transplant-patients-and-others-with-weakened-immune-systems.
American Lung Association. Just how effective are vaccinations for transplant patients? American Lung Association. April 22, 2023. Accessed August 16, 2023. https://www.lung.org/blog/vaccinations-lung-transplant-patients.